Furnace stoker



. l, 1936. H. E. PREsToN FURNACE STOKER Original Filed Oct. 3, 1933 2 Sheets-Sheet l s @iQ m. n @www @i m if@ fwd.

Dec. 1, 1936.

FURNACE STOKER Original Filed 001;. 3, 1933 HA E. PRESTON 2 Sheets-Sheet 2 Patented Dec. 1, 1936 NlTED STATES FURNACE STOKER Herbert E. Preston, Philadelphia, Pa., assignor to American Engineering Company, Philadelphia,

Pa., a corporation of Original application O Pennsylvania ctober 3, 1933, Serial No.

Divided and this application March 6, 1935, Serial No. 9,539

8 Claims.

'Ihis invention relates to improvements in mechanical stokers of the underfeed type, and more particularly to the fuel feeding pushers associated therewith.

One object of the present invention is to provide the fuel pushing elements with renewable nose pieces.

Another object is to provide a fuel pushing element of substantially rectangular form having a body portion and laterally adjustable nose pieces to compensate for irregularities in, and wear or growth of the parts.

A further object is to provide a fuel pushing element with scraping means provided at the sides and bottom thereof so as to prevent fuel siftings from passing therebetween during operation of the stoker.

Other and further objects will become apparent as the description of the invention progresses.

Of the drawings:

Fig. 1 is a longitudinal section of the forward nd of a stoker made in accordance with my in'- vention.

Fig. 2 is a plan view of one of the pushers.

Fig. 3 is a side elevational view of the pusher shown in Fig. 2.

Fig. 4 is a sectional View taken substantially along line 4 4 of Fig. 2, and

Fig. 5 is a sectional end view taken substantially along line 5 5 of Fig. 3.

This application relates more particularly to fuel feeding pushers of underfeed stokers, and is a division of my copending application Serial No. 691,931, filed October 3, 1933, and assigned t0 the American Engineering Company.

Referring to the drawings, the front framework of the stoker consists, in the present instance, of

a plurality of vertical beams l supporting a transverse horizontal composite beam 2, which in turn constitutes a support for the forward ends of rearwardly projecting brackets 3, to which are secured the ram boxes 4. The rear ends of the boxes 4 are secured to and supported upon a series of vertical beams 5, which beams also constitute a a forward support for the inclined beams 6, which constitute the main supporting frame for the stoker retort structure designated generally in Fig. 1 by the reference numeral l. In the present instance the bottom of the retorts are composed of a plurality of fixed plates 8 and pusher elements 9, which are adapted for reciprocation between the plates 8 after the manner well unterstood in the art and illustrated in the drawings. Journaled in the forward ends of the brackets 3 is a main actuating shaft provided with a series of cranks I3 which through connecting rods I4 are connected with the rams I5 which operate within the boxes 4 in a well known manner to discharge fuel entering the boxes through hopper openings l5 into'the upper ends of the retorts. At the extreme upper ends of the retorts and immediately adjacent the mouth of the ram cylinders, the sides of the retorts are provided with replaceable wear plates l0.

At opposite sides of the flange 2| are trunnions 25, which are respectively connected by the short connecting rods 25 with corresponding arms of bell crank levers 2l, these levers being mounted one at each side of the ram boxes 4 upon the ends of a shaft 28 journaled in each instance in a bearing 29 depending from said boxes.

The other arms of the bell crank levers 21 are respectively connected through links 3l with the upper ends of bars 32, these bars being connected through a series of bell cranks 33 and links 34 with rods 35 connecting, as hereinafter set forth, with the pushers 9. The rods 35 are slidably mounted in guide brackets 35, these brackets being secured in vertical arrangement to the upright beams 5, as shown in Fig. 1. The brackets 36 are hanged and these anges 3l through which the brackets are secured to the beams, abut one another and thereby close the spaces between the beams 5 to form a wall of the enclosure beneath the retort which constitutes the air box of the furnace into which the draft air is forced, and from which the air passes to the fuel bed through the tuyres 38. The brackets tinclude extensions from both faces of the flanges 3l, the inner extensions constituting guides for the rods 35, and the outer projecting portions forming aligned guides for crossheads 33 through which the rods 35 extend, and to the opposite sides of which the links 34 are attached. Those portions of the rods 35 which project through the outer extensions of brackets 35 carry sleeves lll which constitute sliding bearings for the crosshead 39. The inner end of the sleeve 4l is threaded and receives a nut 42, this nut limiting the relative movement of the crosshead and the sleeve in one direction. The other end of the sleeve is also threaded for reception of a collar 43, which collar is fixed to the extremity of the rod 35 by means of a shear pin 44.

VIntermediate the crosshead 39 and the collar 43, the sleeve 4l carries an outer sleeve 55, a washer 45 abutting the outer end of this sleeve, and one or a plurality of detachable substantially horseshoe-shaped elements 4l, the latter constituting spacing washers which are readily de- Cil tachable for adjustment purposes. The number and width of the washers 41, and the length of the sleeve l5 determine the extent of the lost motion between the sleeve 4l and the crosshead 39, and assuming a given travel of the crosshead 39, the stroke of the rod 35.

The foregoing device provides a ready means for adjusting the stroke of the rod 35 and the pusher 9 associated therewith from the exterior of the furnace, and by means of the operating connection between the crosshead 39 and the shaft I2, and of the adjusting mechanism described above, it will be apparent that the stroke of each of the rods 35 may be regulated independently of the stroke of the others. From the foregoing description, and with reference to Fig. l, it will be noted that the pushers of the retorts, and the rams respectively associated therewith form operating units, affording a maximum flexibility in the relative adjustment of the various elements of which the unit is constituted.

With reference to Fig. 1, it will be noted that the lowermost of the bell cranks 33 includes a third arm 5l which connects through the medium of the link 58 with the crosshead 39 of the lowermost bracket, and through this crosshead with the lowermost of the rods 35. The uppermost of the rods 35 is connected through a link 59 with the cap pusher 9. The others of the rods 35, with the exception of the bottom, are connected through rods El with the respective pushers, the connection between the rods 6l and 35 being in each instance a flexible one by reason of fixtures 52, which are pivotally connected through pins EU with the inner ends of the rods 35, the fixtures 62 also providing for elongating or shortening the overall length of the rods 6I.

At its inner end, each of the rods 6| carries a hook 63 which engages and grips a transverse pin lll in the associated pusher. The connection between the rods 35 andthe pushers is accordingly a highly flexible one rendering adjustment' and demounting of the various elements a relatively simple one. The lowermost rod 35 is connected through a similar xture 62 and rod Si through suitable operating connection with an extension grate (not shown).

The details of the pushers 9 are shown in Figs. 2 to 5 inclusive. Each of the pushers comprises a relatively open and light base frame 58 which constitutes the main rear portion of the pusher and which has openings 69 in which the pin i0 is mounted. The frame 58 has a forward extension H which constitutes a support for two detachable nose piece sections 12 and 13, these sections, as illustrated, fitting over the extension 'H forming each side thereof and overlapping along a longitudinal center line as indicated at 74 and forming a substantially solid fuel engaging nose for the pushers. The sections 12 and 'i3 in the present instance are corrugated or toothed at the sides as indicated at 15, this formation in operation giving a desirable scraping action preventing accumulations of finely divided fuel within the retort. The extension 1I of the base frame 58 also has at it forward end and on the under side a transverse recess 'i6 for a scraper bar which operates upon the tops of the xed plates 8, as shown in Fig. l. It will also be noted that each of the fixed plates 8 is provided at the tip with a resiiient scraper element 'Il which engages and operates upon the top surface of the pusher nose. These last named sections are secured to the pusher frame by means of bolts 18, as illustrated, the device providing a readily detachable and replaceable nose for the pushers. The scraper elements tend to prevent siftings of coal dust past the pushers.

As shown more particularly in Fig. 2, the bolts i8 extend through laterally extending elongated slots B provided in sections 'i2 and i3. By this arrangement these sections may be extended laterally into engagement with the retort side walls, thereby compensating for any irregularities in the space between said walls, and also for wear and growth of the parts. The pusher elements 9, therefore, may be adjusted so that at all times they will completely fill the bearing opening, and by virtue of the scraper elements 'i5 and TI the passage of siftings past the pusher is reduced to a minimum. This construction also prevents, to a great extent, air leakage into the retorts of the Stoker.

While the structures herein described are admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to limit the invention thereto, but only by the scope of claims which follow.

What is claimed is:

l. A stoker pusher, comprising an open base frame, a plurality of overlapping nose pieces secured to said frame, said nose pieces having means extending over the top, sides, and exposed end of said frame, and a plurality of serrations provided along the sides of said overlapping nose pieces.

2. A stoker pusher, comprising a base frame, and a plurality of nose pieces detachablysecured to said frame, said nose pieces having means extending over the top, sides, and exposed end of said frame, a plurality of serrations provided along the sides of said nose pieces, and said base having a recess provided in the bottom thereof for receiving a scraping element.

3. A fuel feeding pusher for stokers, comprising a substantially rectangular body portion, and renewable vprotective elements extending over the top, sides and the exposed end of said body portion, and means for securing said elements to said body portion, said securing means comprising adjustable means, whereby lateral. adjustment of said protective elements may be effected.

4. A fuel feeding pusher for underfeed stokers, comprising a substantially rectangular body portion, and renewable protective elements extending over the top, sides and the exposed end of said body portion, scraper means provided at the sides of said protective elements, means for securing said elements to said body portion, said securing means comprising adjustable means whereby lateral adjustment of said protective elements may be effected, and said body portion having a recess provided in the bottom thereof for receiving a scraping element.

5. A protective element, comprising one of the parts of a two-part nose piece for fuel feeding pushers, said element being substantially angular in cross section and consisting of a fiat, substantially rectangular top member having a pair of bolt receiving recesses provided therein, a substantially vertical side member, and an end member disposed at substantially right angles to said top and side members, and a flange disposed along the inner edge of said top member, adapted in assembly to overlap with a corresponding flange on the other element of said nose piece.

6. A protective element, comprising one of the parts of a two-part nose piece for fuel kfeeding pushers, said element being substantially angular in cross section and consisting of a flat, substantially rectangular top member having a pair of bolt receiving recesses provided therein, a substantially vertical side member, and an end member disposed at substantially right angles to said top and side members, a flange disposed along the inner edge of said top mem-ber adapted in assembly to overlap with a corresponding ange on the other element of said nose piece, and a series of substantially vertical scraping elements provided on the outer surface of said side member.

'7. A base frame for a stoker pusher, said base frame being of substantially rectangular construction and comprising an enlarged portion and a reduced portion, said portions each having a substantially flat upper member and a pair of parallel side members, means provided at one end of said frame adapting the latter for connection with an operating mechanism, and the lower surface of said frame having a recess for receiving a scraper element.

8. A'stoker pusher, comprising an open base frame of substantially rectangular construction, said frame having an enlarged portion and a reduced portion, providing an extended recess at one end thereof, and a pair of renewable protective elements of substantially angular crosssectional form secured to said reduced portion and neatly occupying said recess whereby the outer surfaces thereof lie in substantially the same planes as the corresponding surfaces of said enlarged portion, overlapping flanges provided on the abutting edges of said protective elements, and a fuel feeding portion provided on each of said elements.

HERBERT E. PRESTON. 

